arm64: dts: rockchip: enable vop2 and hdmi tx on rock-3a

Enable the RK356x Video Output Processor (VOP) 2 on the Radxa
ROCK3 Model A.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20220310210352.451136-4-michael.riesch@wolfvision.net
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20220422072841.2206452-21-s.hauer@pengutronix.de
Signed-off-by: Heiko Stuebner <heiko@sntech.de>